Understanding the Health of California's Neighborhoods: Creating and Disseminating Modeled Sub-County Estimates Using the California Health Interview Survey

Thomas M. Menino Convention & Exhibition Center 

Large-scale, random population surveys using Address-Based Sampling (ABS) are designed to provide a representative overview of the target population, but how can they be leveraged to produce insights for smaller geographic areas that are smaller than those provided for within the overall sample design? The UCLA Center for Health Policy Research conducts the California Health Interview Survey (CHIS), a population-based omnibus public health survey of the diverse population of California, which provides important information on the health, health behaviors and access to health care services of Californians. Conducted since 2001, CHIS data are used extensively in California in policy development, service planning and research, and the CHIS is recognized and valued nationally as a model population-based health survey. The sample design of the CHIS provides for direct estimates at the county level for most California counties, but users of CHIS data are interested in estimates at smaller levels of geography. Using data from the CHIS, we build statistical models that relate individual-level health outcomes to neighborhood-level predictors from the five-year ACS data. The fitted CHIS-based models are then applied to ACS and Claritas data to generate small-area estimates of key CHIS health indicators for Census tracts, ZIP codes, cities, and legislative districts. This approach leverages both individual and contextual information to produce stable estimates for areas with limited or no survey samples. The modeled estimates are calibrated and validated, and then evaluated for statistical stability before being cleared for release. These estimates are then provided to users through the free data visualization tool AskCHIS Neighborhood Edition (NE). This tool enables users to search for top health topics at granular levels of geography and produce tables and thematic maps for easy visualization. It also allows the user to define custom aggregations of geographies, such as clusters of tracts or ZIP codes, in a map-based interface, and output data visualizations for the user-defined geography in real-time. Additionally, pollution and pesticide data from the CalEnviroScreen is included in the tool, in order to allow users to explore health indicators in the context of environmental factors as well as demographic characteristics. Since its inception in 2014, there have been nearly 50,000 queries on AskCHIS NE. This presentation will provide a brief discussion of the modeling methodology used to create the small-area CHIS estimates, and a demonstration of the key features of the AskCHIS Neighborhood Edition tool.

small area estimation

population health surveys

data dissemination tools